The hospital, as a building typology, is historically one of the most understudied and undervalued building types in the field of architecture; yet hospitals are critical, highly specialized public buildings that leave massive imprints on our environment, and on our lives. In recent decades new attention has been drawn to hospital architecture, in particular to the development of techniques for increased efficiency, energy reduction, and interior quality. New buildings are being developed that display greater sensitivity to the qualities of natural light, to the potential healing benefits of access to fresh air and outdoor spaces, and to the carbon reduction that can be recognized by more fully integrating building and mechanical systems.
One of the projects that I am leading at the Integrated Design Lab focuses on the energy impact of hospitals – and how to radically reduce the environmental footprint of healthcare facilities.
This project has evolved over the last five years as we have deepened our understanding of energy use in hospitals. When we first started this work, we were asked by the Northwest Energy Efficiency Alliance to create a body of knowledge surrounding how to meet the 2030 Challenge in a hospital. At that time, it was difficult to even know how much energy an operational hospital used, let alone how to reduce that energy use. Since that time, the work has grown into a national study, funded by the Department of Energy, where we are evaluating the strategies and capital investment required to reach the 2030 Challenge in six of the most diverse climate regions across the U.S. This project, Targeting 100!, gets it’s name from the 2030 Challenge energy reduction goal for hospitals; a 60% energy use reduction from a typical acute care hospital targets approximately 100 KBtu/SF Year, thus the name “Targeting 100!”.
One of the first steps of this project was to identify how much energy average hospitals in the U.S. use. We found out that they use an enormous amount of energy. Buildings use nearly half the energy consumed in the U.S. today and hospitals are the second most intensive energy user per square foot (with fast food topping the energy use intensity for buildings). This adds up to a monumental amount of energy — to put it in perspective, up to 4% of all energy consumed for activities including transportation, industry, and the entire building sector is used by healthcare in the U.S.
To help us understand if there was a clear road-map for achieving the 2030 Challenge, we looked to see if there were built examples already achieving those goals. We found that there are few, if any precedents in the U.S., but our research took us to Scandinavia where hospitals use half to a quarter amount of energy as average hospitals in the U.S. These examples are both energy efficient and have high interior environmental quality with clear connections to the outside environment through daylight, views, and fresh air. Some of the efficiency strategies that are notable include very limited re-heat with most conditioning happening through the air-stream. Radiant heating is common, with spot cooling where necessary through the use of chilled beams. Some examples use displacement ventilation, with air change rates that are comparable to US air changes using this kind of delivery strategy. Ground source heat pumps are often used for storing and extracting heat and heat recovery is common. Exterior dynamic shades limit solar heat gain on the envelope minimizing the need for cooling beyond what is provided through the air systems. These Scandinavian examples are not exactly duplicable in the U.S. for clear differences in climate, culture, and the delivery of care. That prompted our research on understanding how to meet aggressive energy goals such as the 2030 Challenge here in the U.S., following U.S. guidelines for health and building codes.
From our early work in the Pacific Northwest, we understood that there was a big paradox happening in the energy exchange in hospitals. Nearly half the amount of energy being used was for heating, however, the thermal balance point of the building indicated that the building would not need to be heated until it was below 15 degrees F outside. The thermodynamics of hospitals are not working in our favor, but they could be. This information showed that hospitals are internally load dominated — and many of those loads are system imposed loads. This gave us vital information for moving forward — the best target of opportunity is on the heating side. From our previous work in the Pacific Northwest, we also know that attacking the cooling side first brings favorable economic savings. By reducing the cooling demand for the building, although not the dominant load, favorable outcomes such as reduced equipment sizes, reduced internal load, reduced energy, and reduced cost are captured.
Ultimately in our Targeting 100! work, we took an approach of reducing loads first, then utilizing bundled energy efficiency measures to reduce the energy demand of the building. We see that there are synergistic savings in both energy and cost using an integrated, bundled approach to meeting the 2030 Challenge.
One of the big parts of this work is that we feel strongly that it should be grounded in the realities of design, construction and operation of hospitals today. In that light, we have met with numerous stakeholders in those industries across the U.S. and their feedback is influencing our approach to meeting the load reduction, energy efficiency, and cost goals of the project.
The core team for this work was the University of Washington’s Integrated Design Lab, Solarc Architecture and Engineering, NBBJ, and TBD Cost Consultants. Numerous other partners have contributed to this work through their direct evaluation of the research. And, the research is funding by the Northwest Energy Efficiency Alliance, and the U.S. Department of Energy.
Our website offers much more in-depth resources related to this work: idlseattle.com/Health/health_design.html.
Heather Burpee is a Research Assistant Professor of the Department of Architecture at the University of Washington and serves as the Health Design Specialist at the Integrated Design Lab | Seattle (IDL).